/*
 * Copyright (c) 2022 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
const SLASH_SEPARATED_DATES = /(?:(?:[0-3]?\d\/[01]?\d)|(?:[01]?\d\/[0-3]?\d))\/(?:[12]\d)?\d{2}/

// Matches timestamps.
// Examples: "2012-01-02 08:00".
// Note that the reg-ex does not include the
// trailing ":\d\d" -- that is covered by TIME_STAMPS_SUFFIX.
const TIME_STAMPS = /[12]\d{3}[-/]?[01]\d[-/]?[0-3]\d +[0-2]\d$/
const TIME_STAMPS_SUFFIX_LEADING = /^:[0-5]\d/

export default function isValidPreCandidate(candidate, offset, text)
{
	// Skip a match that is more likely to be a date.
	if (SLASH_SEPARATED_DATES.test(candidate)) {
		return false
	}

	// Skip potential time-stamps.
	if (TIME_STAMPS.test(candidate))
	{
		const followingText = text.slice(offset + candidate.length)
		if (TIME_STAMPS_SUFFIX_LEADING.test(followingText)) {
			return false
		}
	}

	return true
}